1. Field of the Invention
The present invention relates to a comparison and calculation circuit for discriminating whether or not a given point exists within a predetermined linear area defined by a pair of boundary values, and more specifically, to a circuit for discriminating whether or not a given point exists within a predetermined area and for outputting a coordinate value of the given point in a new coordinate system having a lower limit point of the predetermined area as the origin of coordinate.
2. Description of Related Art
In the prior art, comparison and calculation for discriminating whether or not a given point exists for example within a predetermined linear or one-dimensional area have been performed in a software means, namely by executing a sequence of operation instructions. In this manner, two registers in a register group provided in a computer are assigned for presetting a pair of boundary values of the predetermined area, and a value of the given point is compared with a value stored in each of the registers. If it is judged that the value of the given point is larger than a lower boundary value of the present boundary value pair and smaller than an upper boundary value of the preset boundary value pair, it can be decided that the given point exists within the predetermined linear area.
For the above mentioned discrimination, however, the lower boundary value must be set in a register assigned for the lower boundary value and the upper boundary value must be set in another register assigned for the upper boundary value. Therefore, when a pair of boundary values are given, a large-and-small relation between the pair of given boundary values must be discriminated in advance so as to ensure that the lower boundary value is preset in a register assigned for the lower boundary value and the upper boundary value is preset in another register assigned for the upper boundary value.
In addition, if the number of areas to be discriminated increases, the execution time for required operation correspondingly increases, and finally, it becomes impossible to perform all the required operation within a given period of time.